Conventional input devices, such as computer mice, typically employ optical sensors, track wheels or track balls to control the motion of a cursor or other navigational object on a computer display screen. Other types of input devices that measure a force imparted onto the input device typically incorporate one or more accelerometers for sensing acceleration forces exerted on the input device as it is moved by a user. A velocity of the electronic input device may be calculated and estimated by integrating the measured acceleration over time, and a position estimate of the input device may be calculated by integrating its velocity over time. In this way, motion of an accelerometer-based input device may be translated to motion of a cursor or other navigational object on a computer display screen.
However, many existing methods for tracking two-dimensional motion with accelerometer-based devices do not adequately take into account variations in three-dimensional orientation. For example, an orientation change of only about 0.5 degrees from the horizontal plane can contribute up to 10 mG acceleration in a plane of motion, which can be significant with respect to human initiated motion. Therefore, there is a need for systems and methods that account for a tilt in a plane of motion so as to provide a result that is more indicative of a user's intended motion of the input device.